杏吧原创

DOUG WHEELOCK never really liked his spacesuit. 鈥淚t may look cool, but it鈥檚 35 years old, smells like a locker room and there鈥檚 some discolouration on the inside,鈥� he says. Yet that dilapidated old thing was all that stood between him and deadly cold nothingness during the NASA astronaut鈥檚 six spacewalks. 鈥淚t鈥檚 actually kind of scary when you think about it,鈥� he says.

Wheelock is talking about the puffy-looking white suit with the reflective visor that NASA calls the Extravehicular Mobility Unit (EMU). These suits are among the most famous pieces of clothing ever worn, but they are well past their shelf life.

When Apollo astronauts visited the moon in the 1960s and 70s, they stayed for a few hours, so it didn鈥檛 matter if the suits were a little on the basic side. Now, though, space agencies and commercial companies are planning to revisit the moon with more ambitious objectives, like setting up long-term bases. With Mars in their sights too, they are working to refresh the space wardrobe. That means it鈥檚 out with the iconic white get-up, and in with a new generation of spacesuits that can combat withering cold, intense radiation, piercing dust and muscle deterioration 鈥� and do it all for longer than ever.

There鈥檚 no mistaking the importance of this pursuit for our space exploration ambitions. 鈥淎 spacesuit is actually an anthropomorphic, miniature spacecraft with the complexity of a larger space vehicle,鈥� says engineer at the European Space Agency (ESA). NASA has already spent at least $200 million on its spacesuit renewal programme, and now the first designs are leaving the dressing room for tests.

When NASA first put people in orbit in the 1960s, they sported modified pressure suits from high-altitude jet planes. By 1981, that had evolved into the EMU, which astronauts still wear when they venture outside the International Space Station (ISS).

These suits come in sections, and only a few handfuls of each section were ever made. Take the life-support backpacks, the most expensive and complicated part: only 11 of 18 originals are still in working order. If we were to build new EMUs today, NASA estimates they would cost perhaps $250 million apiece, partly because the technology is so outdated that it is hard to reproduce.

Meanwhile, the need to do something about our ageing space apparel has become ever more apparent. In 2013, astronaut Luca Parmitano was on a spacewalk when water began leaking into his helmet and floated into his nose and mouth, raising fears he might drown. Fellow astronaut Christopher Cassidy averted catastrophe by quickly helping him back inside the ISS.

The EMU isn鈥檛 the only garment approaching expiry. Astronauts must cope with a diverse set of environments, during launch, spacewalks and potentially planetary exploration. Inside a launch capsule on their way into space, they need a suit that will pressurise quickly if the life-support systems fail. It must also fit in the capsule鈥檚 cramped seats and plug into its life support systems. The only vehicle shuttling people to the space station at the moment is the Russian Soyuz, so astronauts and cosmonauts alike wear the matching Russian Sokol (or 鈥淔alcon鈥�) suit during launch and re-entry.

鈥淭he 鈥榮pace hoodie鈥� design is far less clunky than the old fish-bowl helmets鈥�

That suit is even older than the EMU, but now new capsules such as NASA鈥檚 Orion and Starliner are in preparation. The Orion capsule is due to make its first trip to the ISS in the early 2020s. Both capsules need bespoke suits to go with them.

NASA has contracted Boeing to make the Starliner capsule and suits, and the firm unveiled the prototype garb in January 2017: a bright blue suit made with lighter materials and more flexible joints than previous offerings. It has a soft helmet that is attached to the suit like a hood; astronauts pull it over their heads and zip it down in an emergency. This 鈥渟pace hoodie鈥� design is far less clunky than the traditional fish-bowl helmets. 鈥淚n the last 60 years, there鈥檚 been no suit lighter than this one,鈥� says Kavya Manyapu, a Boeing engineer.

That lightness isn鈥檛 just for comfort. Every gram of material on a rocket adds to the cost of fuel, so for private space firms such as SpaceX, cutting down on weight could provide a commercial advantage. The company is developing its own suit for its reusable Crew Dragon capsule, which is scheduled to start carrying people to the ISS in August. We know little about the suit yet, but snaps posted online by the firm鈥檚 founder Elon Musk show a sleek black and white design.

A slinky number is fair enough for a transport capsule, but it wouldn鈥檛 be sufficiently robust for spacewalks. For US astronauts, the only option there remains the EMU. For Russian cosmonauts, there鈥檚 the Orlan suit, which had its first outing in 1977.

NASA has been working on replacements for the EMU since at least 2007 鈥� and it鈥檚 looking to future-proof its vision. Its new suits aren鈥檛 just designed for spacewalks, but for walking and spending significant time on extraterrestrial surfaces.

In the first instance that means the lunar surface. Just last month, US President Donald Trump signed a directive instructing NASA to focus its efforts on human space exploration, particularly the moon. The Apollo astronauts took just 18 moonwalks, exploring six small areas. Future explorers would be aiming to go further afield, hunting for reservoirs of water under the moon鈥檚 surface and clues about the birth of the solar system hidden in the rock. They might also build a moon base as a way station and testing ground for missions to worlds further afield.

That鈥檚 something for which the iconic Apollo moonwalk suits won鈥檛 cut the mustard. 鈥淭he spacesuit technology developed during the mid-20th century was originally designed for short-duration missions to the moon,鈥� says Marwhala Madill. The suits were uncomfortable and tough to manoeuvre in. The Apollo astronauts couldn鈥檛 bend down to pick up rocks; they had to use a pole.

The EMU evolved from those suits and isn鈥檛 a lot better. It has a limited field of view and no neck joint, which means astronauts must turn their entire bodies if they need to look at anything that isn鈥檛 in front of them. 鈥淣inety per cent of the battle with an EMU suit is getting into the correct body position to get at whatever it is you鈥檙e trying to repair,鈥� says Wheelock.

designs NASA鈥檚 new spacesuits, and since 2013 that has included prototype 鈥渆xtra-vehicular鈥� suits called the Z-1 and Z-2. These are heaps better than the Apollo and EMU suits, she says. The Z-2 shoulder joints and lower body have a broader range of motion than previous suits, with a waist that can turn and flex so that astronauts can look around and walk more easily. It is also more modular than previous versions, with different arm and leg lengths so the suit can be personalised. It has already performed well in tests in NASA鈥檚 in Houston, Texas. This contains a giant pool used to simulate microgravity where astronauts can work with a full-size mock-up of the ISS.

Even so, Ross admits that fundamental advances in materials science are needed before spacesuits can actually be described as comfortable. For her and her fellow spacesuit designers, the stickier problem is moon dust. On Earth, tiny meteors burn up in the atmosphere, but on the airless moon, space debris can hit the surface at 160,000 kilometres per hour, melting and smashing rocks and sticking the shards together in jagged dust particles. This dust is not only nastily abrasive, but has a static electric charge, and so sticks everywhere. It was a nightmare for the Apollo astronauts: it stuck to their helmets, gummed up their suit joints, and grated through layers of spacesuit material. When they tracked it into the lunar module they breathed it in and contracted 鈥渟pace hay fever鈥�.

A lunar dust buster that would suck the stuff up has long been tossed around as a solution. The idea of one prototype called SPARCLE, developed in 2009, was to spray the dust with electrons to render it negatively charged, then suck it into a positively charged nozzle.

SPARCLE looks to have been mothballed because the researchers involved either moved on or retired, but a similar device is still under development. This electrodynamic dust shield casts an electric field over solar panels, electronics and potentially suits, to prevent dust from accumulating on them. NASA is planning to start testing it on the ISS.

It would still be prudent to make suits that are tough, though, so Ross and her team are working on an Environmental Protection Garment that will form the Z-2 suit鈥檚 outer layer. They are trying to figure out which fabrics will be able to withstand the grating moon dust and how to attach those fabrics to the rest of the suit to minimise leaks.

Once the fabrics are chosen, Ross鈥檚 team do standard stretching tests before the crucial 鈥渞ock tumbler test鈥�. This is exactly what it sounds like: swathes of fabric are tossed around with rocks and moon dust to see how badly the fabric degrades. Real moon dust is rather too precious for this purpose 鈥� the Apollo astronauts brought back only about 380 kilograms of the stuff 鈥� so the first step for Ross is to get her hands on some ersatz dust (see 鈥�Making moon dust鈥�).

Some people are suggesting more radical anti-dust measures in next-generation spacesuit design. For the most part, astronauts exit rovers or landers using a mechanism that first shuts them in a chamber, then depressurises and opens its other end to space: an airlock. But that way, the spacesuit has to be traipsed through the airlock.

Instead, why not attach the spacesuit directly to the side of the craft and let the astronaut climb in through a hatch in the back? That would stop the dust ever coming inside. This 鈥渟uitport鈥� idea was , and a team from the agency鈥檚 Langley Research Center proposed installing suitports in future rovers in 1995. Soon afterwards, a team at another NASA lab tried it out on Earth, installing such a suitport in a personnel carrier used to clean up hazardous materials. And in 2012, NASA built a prototype Z-1 suit with matching suitport and tested it in a vacuum chamber. Most people managed to climb in and out fairly easily, but a couple .

鈥淔or spacewalks, a suit with a more flexible torso would be a boon鈥�

Wheelock says the Z-2 suit may be ready for the ISS by 2020, but NASA also has another spacesuit research project up its sleeve. The Prototype Exploration Suit (PXS) is primarily billed as a suit for spacewalks, where its more flexible torso would be a boon, but it is also a testbed for more speculative technology 鈥� some of which might be useful on Mars.

There, everything will be harder. The dust is less spiky than on the moon, but Martian dust grains get more highly electrostatically charged as they rub together in the thin, dry air, to the extent that they might disrupt electronics if brought back into a spacecraft. The dust can also become acidic and corrosive when combined with oxygen and water vapour, which spacesuits tend to be full of 鈥� making something you really do not want to inhale.

And on Mars, there is even less chance than there is on the moon of resupply in the event of an accident. That鈥檚 why it is good news that at least some parts of the PXS can be 3D printed. At the moment, this functionality is to make suits adaptable to different bodies, but it could also mean that Mars explorers could print their own replacement suit parts.

That is far from a done deal, but our attire for at least one part of any future Mars mission does look sorted. The ESA has developed a 鈥渟kinsuit鈥� made from elastic material that replicates gravity by putting just the right amount of pressure on the body. This should counteract the muscle wastage and bone problems that come from a long journey in microgravity. Best of all, these suits are painstakingly fitted to each astronaut, which means no rubbing up against other people鈥檚 sweat stains. Doug Wheelock will be pleased.

This article appeared in print under the headline 鈥淐osmic couture鈥�